[PATCH] gdb: fix ppc-sysv-tdep.c build on 32-bit platforms

[PATCH] gdb: fix ppc-sysv-tdep.c build on 32-bit platforms

[John Baldwin]

The previous code triggered the following error on an i386 host:

/git/gdb/gdb/ppc-sysv-tdep.c:1764:34: error: non-constant-expression cannot be narrowed from type 'ULONGEST' (aka 'unsigned long long') to 'size_t' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
              unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
                                        ^~~~~~~~~~~~~~~~~~~~~
/git/gdb/gdb/gdbtypes.h:2043:31: note: expanded from macro 'TYPE_LENGTH'
                              ^~~~~~~~~~~~~~~~~~
/git/gdb/gdb/ppc-sysv-tdep.c:1764:34: note: insert an explicit cast to silence this issue
              unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
                                        ^~~~~~~~~~~~~~~~~~~~~
                                        static_cast<size_t>( )
/git/gdb/gdb/gdbtypes.h:2043:31: note: expanded from macro 'TYPE_LENGTH'
                              ^~~~~~~~~~~~~~~~~~
1 error generated.

Fix this by using gdb::make_array_view.
---
 gdb/ppc-sysv-tdep.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
index 5255cea43e3..9a3b02f028d 100644
--- a/gdb/ppc-sysv-tdep.c
+++ b/gdb/ppc-sysv-tdep.c
@@ -1761,7 +1761,8 @@ ppc64_sysv_abi_return_value_base (struct gdbarch *gdbarch, struct type *valtype,
 	      /* Fixed point type values need to be returned unscaled.  */
 	      gdb_mpz unscaled;
 
-	      unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
+	      unscaled.read (gdb::make_array_view (writebuf,
+						   TYPE_LENGTH (valtype)),
 			     type_byte_order (valtype),
 			     valtype->is_unsigned ());
 	      return_val = unscaled.as_integer<LONGEST> ();
-- 
2.34.1

Re: [PATCH] gdb: fix ppc-sysv-tdep.c build on 32-bit platforms

[Tom Tromey]

>>>>> "John" == John Baldwin <jhb@FreeBSD.org> writes:

John> Fix this by using gdb::make_array_view.

Looks good.  Thank you.

Tom

Re: [PATCH] gdb: fix ppc-sysv-tdep.c build on 32-bit platforms

[Kevin Buettner]

Hi John,

LGTM.

Kevin

On Fri, 28 Jan 2022 11:24:25 -0800
John Baldwin <jhb@FreeBSD.org> wrote:

> The previous code triggered the following error on an i386 host:
> 
> /git/gdb/gdb/ppc-sysv-tdep.c:1764:34: error: non-constant-expression cannot be narrowed from type 'ULONGEST' (aka 'unsigned long long') to 'size_t' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
>               unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
>                                         ^~~~~~~~~~~~~~~~~~~~~
> /git/gdb/gdb/gdbtypes.h:2043:31: note: expanded from macro 'TYPE_LENGTH'
>                               ^~~~~~~~~~~~~~~~~~
> /git/gdb/gdb/ppc-sysv-tdep.c:1764:34: note: insert an explicit cast to silence this issue
>               unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
>                                         ^~~~~~~~~~~~~~~~~~~~~
>                                         static_cast<size_t>( )
> /git/gdb/gdb/gdbtypes.h:2043:31: note: expanded from macro 'TYPE_LENGTH'
>                               ^~~~~~~~~~~~~~~~~~
> 1 error generated.
> 
> Fix this by using gdb::make_array_view.
> ---
>  gdb/ppc-sysv-tdep.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/ppc-sysv-tdep.c b/gdb/ppc-sysv-tdep.c
> index 5255cea43e3..9a3b02f028d 100644
> --- a/gdb/ppc-sysv-tdep.c
> +++ b/gdb/ppc-sysv-tdep.c
> @@ -1761,7 +1761,8 @@ ppc64_sysv_abi_return_value_base (struct gdbarch *gdbarch, struct type *valtype,
>  	      /* Fixed point type values need to be returned unscaled.  */
>  	      gdb_mpz unscaled;
>  
> -	      unscaled.read ({writebuf, TYPE_LENGTH (valtype)},
> +	      unscaled.read (gdb::make_array_view (writebuf,
> +						   TYPE_LENGTH (valtype)),
>  			     type_byte_order (valtype),
>  			     valtype->is_unsigned ());
>  	      return_val = unscaled.as_integer<LONGEST> ();
> -- 
> 2.34.1
>